Biological samples, e.g., plant tissue samples, are routinely tested for the presence of the gene (DNA) and whether the gene product (protein) is expressed. Currently, tissues from organisms, such as the plants or animals, have to be sampled separately for each of these tests. If both the protein and DNA can be extracted from the same sample, then a significant savings would be achieved in both consumable costs as well as time and labor savings. Methods exist for simultaneous extraction of DNA/RNA/protein but the resulting protein, extracted with buffers that denature the protein, is not suitable for measurement in quantitative methods such as enzyme linked immunosorbent assay (ELISA); it can only be measured by methods that can employ denatured proteins (e.g., western blot). Existing methods isolate the nucleic acid components first to prevent any potential degradation of this material, but this process will cause the denaturation of the proteins in the mixture. Thus, the present invention overcomes previous shortcoming in the art by providing compositions and methods for dual extraction of undenatured protein and nucleic acid from a single tissue sample.